Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 155: | \[{21^{155}-1\over20}\] | 5 × 311 × 40841 × 519169711 × 4540713283<10> × 397280183491<12> × 3936833990413<13> × 272581865551637989<18> × 331444555707209696951<21> × 10051236464468058997903023288131<32> × 2066946122082360949514509181598305257599462100251009362457171229571826170644439791511<85> |